The Celestial Bodies - Lesson Summary

A night when one side of the moon is completely visible from the earth is called a Full Moon night or Poornima.

A night without a moon or a no moon night is called a New Moon night. In Hindi, a New moon night is called Amavasya.

The night sky is full of innumerable twinkling bodies. These bodies are called stars. They are very big and hot celestial bodies made up of gases and emit large amounts of heat and light. Stars closer to earth appear brighter. The sun is the star closest to us.

Clusters of billions of stars along with dust and gas are bound together by gravity. Such clusters of stars are called galaxies. Millions of galaxies together make up our Universe. Some stars in ancient times did not twinkle and just glowed steadily. These celestial bodies were called the “wandering stars”. Today, we recognise these bodies as planets.

A planet moves around a star along a fixed path and does not have its own heat and light but receives heat and light from the star around which it moves. There are seven other planets that move around the sun in fixed paths. Some planets have other celestial bodies moving around them. These celestial bodies are called satellites. The moon moves around the earth; it is the earth’s satellite.

It was observed that different groups of stars formed unique and beautiful patterns. These patterns were given a common name, constellations. There are, in all, 88 constellations known to man. Ursa Major or the Big Bear is one of the most well-known and easily recognisable constellations. Within a constellation, small star patterns can also be observed. These stars patterns are called asterisms. One such asterism is formed by the seven brightest stars of the Ursa Major. This asterism is called the Small Bear or the Saptarishi in Hindi. The two stars that form the edge of the bear’s bowl are called the Pointer Stars.

The pointer stars point to the Polaris or the Pole Star. The Polaris seems to remain aligned to the earth’s North Pole. This is the reason why the Polaris is also called the North Star. In Hindi, the Polaris is called the Dhruva Tara. The sun’s light is very bright. Hence, the other celestial bodies pale off and are barely visible to the naked eye. The planet Venus is another celestial body that can be seen during the day. Venus is also called the Morning Star.